The invention generally relates to fluid injection apparatus and, more particularly, relates to manually operated syringes.
Many medical procedures require the injection of fluid. One example is angiography. Angiography is a procedure used in the detection and treatment of abnormalities or restrictions in blood vessels. During angiography, a radiographic image of a vascular structure is obtained by injecting radiopaque fluid or contrast through a catheter into a vein or artery. Vascular structure fluidically connected with the vein or artery in which the injection occurs is filled with the contrast material. X-rays are then passed through the region of the body in which the contrast material was injected, with the x-rays being absorbed by the contrast material, creating a radiographic outline or image of the blood vessel containing the contrast material. The x-ray image of the blood vessels filled with the contrast material is usually recorded onto film or videotape and then displayed on a fluoroscope monitor.
The speed with which the injection of contrast occurs enhances the resulting radiographic image because the speed of injection counteracts the flow of blood through the vessels that continually carries or flushes the contrast away. The faster the injection of contrast means a higher concentration of the contrast during the x-ray imaging and therefore a higher radiopacity of the blood vessels. Due to the high viscosity of the contrast material, and the flow resistance in the catheter and other fluid channels, the force required for rapid injection of a contrast is relatively high.
An additional factor contributing to the high forces required for plunger depression is that as current technology has evolved, the catheters used for angiography have reduced in size. The outlet diameters of the catheters have been reduced to four or five French size catheters. As a result, the force required to inject into the arteries has increased significantly.
Currently, manual syringes are used to inject contrast into most arteries. When large flow rates of contrast are required, as is the case for ventrilography (injecting into the left ventricle), a power injector is typically used because manual syringes cannot be operated with sufficiently high flow rate due to the inability to apply enough manual force on the syringe plunger. The power injector is operated by first setting a flow rate and an injection volume. The operator then activates the system by pressing a button on a hand controller which actuates a motor or the like for injecting the contrast. Examples of such power injectors are disclosed in U.S. Pat. Nos. 5,515,851 and 5,916,165.
However, while such power injectors are preferable in certain applications, in other instances, it would be advantageous to use a manual syringe. One advantage of using a manual syringe is that the operator is provided with more direct control of the injection. For example, if resistance is encountered during the injection process, the operator can detect the resistance due to an increase in the pressure, and thus the force required to manually depress the plunger.
It would therefore be advantageous to provide a fluid injection apparatus which enables the injection to be performed manually, but which reduces the force required for such manual operation without employing a power injector.
In accordance with one aspect of the invention, a fluid injection apparatus adapted to inject fluid is provided which comprises an input device, a catheter, and an improved visualization device. The catheter is in fluid communication with the input device. The improved visualization device is adapted to increase the speed with which fluid may be injected.
In accordance with another aspect of the invention, a method of manually injecting fluid is provided which comprises the steps of retracting a plunger from a syringe cylinder and drawing fluid into the cylinder, depressing the plunger into the cylinder forcing the fluid out an outlet of the cylinder, increasing the speed with which fluid may be injected, and injecting the fluid into a patient.
In accordance with another aspect of the invention, a manually operated fluid injection apparatus is provided which comprises a syringe, a manifold, a fluid line, a catheter, a source of fluid, and a heater. The syringe includes a movable plunger, while the manifold includes a plurality of inlet ports in first and second ends. The syringe is connected to the first end of the manifold. The catheter is connected to the second end of the manifold. The source of fluid is in communication with one of the manifold inlet ports via the fluid line, while the heater is operatively associated with one of the syringe, manifold, fluid line, catheter, or source of fluid.
In accordance with another aspect of the invention, a manually operated fluid injection apparatus is provided which comprises a syringe, a manifold, a fluid line, a catheter, a source of fluid, and an expandable ring. The syringe includes a movable plunger, while the manifold includes a plurality of inlet ports in first and second ends. The syringe is connected to the first end of the manifold. The catheter is connected to the second end of the manifold. The source of fluid is in communication with one of the manifold inlet ports via the fluid line, while the expandable ring is associated with the catheter and is expandable after catheter insertion and prior to injection to constrict blood flow.
In accordance with another aspect of the invention a manually operated fluid injection system is provided which comprises a manipulable input device, and a heater associated with the input device and adapted to increase the temperature of fluid prior to injection.
In accordance with another aspect of the invention a manually operated fluid injection system is provided which comprises a manipulable input device, a catheter connected to the input device, and an expandable member associated with the catheter and adapted to expand after the catheter is inserted into a patient to restrict blood flow during injection.
These and other aspects and features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.